Principal Software Engineer

Principal Software Engineer
Portsmouth | Hybrid, 3 days onsite
£75,000–£85,000 plus bonus and benefits

Want to work on groundbreaking projects within the defence industry?

Are you a hands-on technical leader with strong C++ and Unreal Engine expertise and want to work at the forefront of complex, performance-critical software delivery within defence?

The role combines advanced engineering with genuine technical authority, shaping how simulation-driven and autonomy-focused systems are designed, built and evolved.

The position sits within a fast-growing software and data science consultancy delivering end-to-end solutions in the defence industry. You will work closely with subject matter experts and senior stakeholders on high-impact programmes spanning modelling and simulation, autonomy, geospatial systems, synthetic environments and digital twins.

This is a true principal-level role. You will remain deeply technical while setting direction, leading teams and acting as the technical authority across projects.

• Leading the design and delivery of complex software solutions using C++ and Unreal Engine
• Acting as technical lead across modelling and simulation, wargaming and autonomous systems
• Applying mathematical and computational techniques to solve real-world problems
• Owning key technical decisions across architecture, tooling and performance
• Mentoring engineers and enabling high-performing delivery teams
• Delivering technical consultancy engagements and leading selected projects
• Building trusted relationships with customers and stakeholders
• Supporting bids, proposals and technical reporting

• Extensive experience, typically 15+ years, delivering high-performance software
• Proven technical leadership at Principal or Technical Lead level
• Strong hands‑on expertise in C++ and Unreal Engine
• Background in simulation, autonomy, robotics or game-engine-driven environments
• Experience working with large, complex codebases and performance constraints
  
  Strong stakeholder management, communication and influencing skills

• Salary up to £85,000, flexible for exceptional technical leaders
• 7% employer pension contribution
• Vitality private healthcare
• 25 days holiday with the option to buy or sell additional days
• Life assurance
• EV salary sacrifice scheme
• Discretionary bonus linked to company performance
• Structured mentoring and ongoing technical development